Blizzard gives us a breakdown of all of your options
[Update: The pre-patch is now live, and you can begin the process of transferring your characters between each classic game. This is what your launcher will look like going forward. There’s an option for “Burning Crusade Classic” as well as “World of Warcraft Classic.”
Upon logging in I was able to make the switch and it was relatively painless. After changing one of my Druids over to Burning Crusade, the game told me I could clone my character into WoW Classic for $15 at a later date, which I’m electing not to do. Simple enough!
I gotta say, fumbling of the clone fee aside, it really takes me back seeing that Dark Portal splash screen again.]
WoW Classic is about to be cleaved in two.
On one side of the Dark Portal: Classic Classic. On the other, Burning Crusade Classic. We knew this day would come, and for months we tried to figure out how this would actually work. But just recently via Blizzard’s BlizzConline stream, we know how it’ll work. And it involves two completely different servers.
When May 18 hits, the “pre-expansion patch” will go live in Classic. At this point you’ll have two choices: you can bring them forward into the new expansion or stay in the old hotness (which will confusingly be brought forward into new “old” servers). Or, you can “clone them” for a fee.
Blizzard is now ready to fully explain how it’s all going to work, through this detailed blog post here. This is the gist of how cloning happens: “Upon installing and logging into the other game, in this case, World of Warcraft Classic, you’ll see [your character] listed and is greyed out. The text under her name now reads as, ‘Clone Available.’ A Clone icon will appear next to Thuata’s name as shown below. A tip will appear on mouse-over of the Clone icon. If you click the Clone icon, a confirmation window with more information will appear. It shows the ‘cloned’ date of the character which includes all progress on the character up to that date.” Then you pay the fee, and you’re good to go.
Between the video below and this full rundown, you should be fully set to log in on May 18 and plan your course. As a reminder, Blizzard recently changed the price for cloning characters from $35 to $15.
I’m planning on just bringing everything forward, if Blizzard keeps up this process of continuing on with expansions. It’s a lot less overhead and I don’t mind slowly replaying the game progression style all over again.
Playing Ahead: Making Choices in WoW Classic [Battle.net]